So I was driving my WK while towing my XJ and trailer (~6500 lbs) and, as I accelerated away from a toll booth, I lost power. I had down-shifted the tranny to 2nd gear as I approached the tolls (I have EZ-Pass, so I didn't have to stop), and I hadn't up-shifted as I accelerated. The engine RPM spiked up to ~3500 when I hit the gas, and then power was lost... Kind of felt like the tranny wasn't engaged - engine ran just fine, but no power.

Pulled over, discovered diesel pouring out of the bottom of the engine compartment. Had the WK towed to a Jeep dealer, left it (was a Sat night), and headed home with my trailer in the XJ.

Following Monday the dealer looked at the WK. They said the O-ring on one of the fuel injectors became unseated causing the leak. The dealer's mechanic reseated it, reassembled the fuel rail, and the WK was runnng fine again. Picked the WK up yesterday (I live ~2.5 hrs from this particular dealer in another state) and drove home without issues. Everything was covered under warrenty (the WK has ~3750 miles on it).

While I was at the dealer I inquired about buying O-rings (I thought they were replaced), but found they are not sold separately - in fact the entire fuel rail assembly, including injectors, is sold as a unit.

Knowing what failed, I probably could have pulled it apart myself on the side of the highway, fixed it, and kept going - I had all my tools with me.

Anyway, wondering what you guys think about this type of failure. Anyone with any experience of this type of failure?

Not heard of this failure before but it is a very high pressure fuel system so i suppose the smallest error in installing the rail could cause the o-ring to fail prematurely. That doesn't sound right that it is all sold as one piece. Did they tell you what the price was for the fuel rail and injectors?

sounds like a situation where you should ask the have the defective parts back (versus the dealer throwing them in the dumpster). then you'd have some spare parts, though chrysler or mercedes may want to have the broken parts sent back to the factory for analysis, I have heard of that happening in unique situations.

It's a good idea, but the dealer would probably turn you down. While I can't say if they do or do not throw it in the dumpster....I can say they should not! That whole assembly is probably thousands and thousands of dollars and they should recondition them. I know those injectors are big money on their own....this is part of the reason these companies go bankrupt....all that just for a bad o-ring seems like major overkill.

but, it never hurts to ask to have the old parts back, worst that can happen is they say no.

I had a buddy working as a dodge mechanic and he would bring me free "dumpster" parts all the time. I replaced my cracked grille with one that had a minor blemish. I had a spare fuel pump and a spare headlight.

To clarify - No parts were replaced, so there was nothing for me to ask them to return... They reinstalled the O-rings which had become unseated. Presumably they inspected it to be sure it was OK. The work order specifically says "inspected return line, reseated O-rings, and reassembled".

I didn't ask for the price of the fuel rail / injectors.

This WK is one of the ones that had a fuel system replaced as a result of contamination (I bought it ~3 months ago), so when I got it there was a new fuel system installed from the factory, including injectors/fuel rail.

Hey Guy's
Normally the dealer is required to hold onto any warranty parts for 90 days or untill the factory tells them to dispose of the parts.. And I mean they are supposed to destroy the old parts before putting them in the trash..
Ron

So, I just completed my road trip from NH to Moab, UT (and back)... For the trip out to Utah and back I was using my WK to tow my XJ. I had the o-rings in the Wk's fuel system fail on me a few times and leak during the trip and now I can explain what it is -- I had to stop on the side of the road and fix it 3 times!

The problem is that the Mercedes engineers who designed the fuel system in the 3.0L CRD cheaped out when they designed the fuel injector fuel return system. There are 6 metal stems which come out of the top of the engine, adjacent to the fuel injectors (one per injector). At the tip of each stem is a flange and an o-ring. The excess fuel that wasn't pumped through the injector comes up these tubes then through a T-fitting (plastic) and into some 1/8" ID tubing to return the excess fuel. All these fittings are linked together in a daisy chain on each side of the engine, so if one goes the whole system loses pressure.

The problem is the stupid plastic T-fittings are retained with a collar you push down (it "locks" in to place) to squeeze the plastic fitting against the flange at the end of the tube, which is presumably sealed by the o-ring... Somehow these stupid fittings come loose on my engine and result in leaking fuel. When they come off the engine completely loses fuel pressure.

This whole mess is located under the two black foam pads on the top of the engine under the engine cover, so it isn't too hard to access (couple of 10mm bolts to remove the cover, one to release the air intake, and loosten the intake clamp where it goes into the turbo).

The first day of my trip I pulled onto the highway after 1 hr of driving and a brief stop and one of these clips let go causing a fuel leak and no pressure. I was able to clip the one which came off back together and discovered a 2nd clip was loose. I checked the other 4 and they seemed to be tight. I also disabled my PowerBox CR+ (set it to 0 -- stock mode).

The 2nd day of my trip I got a check-engine code and get stuck in limp-mode... I cleared the code w/ my trusty code reader, but checked the fuel returns because the code indicated "low fuel pressure" -- no leaks, but instead I discovered an exhaust leak around 2 of the fuel injectors, which had come loose. After tightening up the fuel injector retainer bolts (one per injector) it seemed the engine was OK -- no more exhaust leaks. No other problems were had on the way out, but the mileage sucked (10-13 mpg, though I was towing 7200 lbs... On the way back it was 2-3 mpg better).

Fast forward to the first day of my drive back, 6 days after I arrived in Moab... The WK had sat for the week and only been used 1 day immediately before we left to return home (no towing - just driving around town). While I had the engine idling in the parking lot of the hotel I smelled diesel... Looked underneath and saw a puddle of diesel... Pulled the covers off and sure enough -- another of these stupid clips had somehow come loose and started leaking, different from the first 2. I pulled the clip on the leaking injector return, reseated / re-clipped it and the leak stopped.

I'd give a lot to meet the guy who designed this rinky-dink POS fuel system...

Over the summer I had done some medium duty towing with the WK -- pulled an 18' Searay ski boat -- after the original incident. Hadn't noticed any fuel leaks or smelled diesel. Hadn't had any problem since the first incident, which also occurred when towing my XJ.

Only good news is that other than these issues the WK did an awesome job as a tow vehicle for my XJ + 24' car trailer.

thanks for the update, quite often we never hear about what's happened since a fix.

at first I assumed your TDC is causing the problem, but justa4banger may be on to something regarding a clogged return line. I'd also remove the TDC just in case its faulty, you have it set to 0 anyway.

anyway, yours is the first I've read about having the problems you are describing.

Hi
Missed this first time round sorry. I have had this issue but not common and most of the time it's after someone has been playing with the fuel system. The return is also under pressure as it goes back to the fuel filter (so you get warm fuel) and is under pressure from the lift pump. I would get the return line bundle changed.
Regards,
Merlin.